Through advancements in metering infrastructure, the collection of meter readings that quantify the consumption of utility services (i.e., natural gas, water, electricity, etc.) is being automated. In an automated meter reader system, “endpoint devices” coupled to utility meters are typically used to collect and record the meter readings for transmission to reader devices. The endpoint devices that are configured to communicate consumption data in this way are commercially available and increasingly being installed in homes, businesses, and the like.
In some automated meter reader systems, the endpoint devices are configured to record meter readings at predetermined intervals and to transmit the meter readings to a reader device. In some cases, the endpoint devices include a microprocessor-implemented real time clock that is used when recording meter reading data or transmitting meter reading data. In such cases, synchronization among various endpoint devices and reader devices is necessary within the automated meter reader system. However, such synchronization has been a challenge due to the time differences among time zones, daylight savings time adjustment, leap year adjustment, etc.
In other implementations, each endpoint device includes a simple timing device, which eliminates the need of real time synchronization among the endpoint devices. In these implementations, the reader device, which collects meter reading data from the endpoint devices, typically adds a timestamp to the collected meter reading data.
In an ideal environment, the time-stamped data are processed later in a processing system and thus the reader device does not need to perform much computation other than adding timestamps. However, if the endpoint device time has drifted, the reader device cannot simply timestamp the collected data. In most cases, the reader device and the endpoint device exchange several messages to determine the time drift and to generate accurate timestamps for the collected data. For some types of meter reading systems, in particular, for a meter reading system that includes a small number of reader devices that collect meter readings from a large number of endpoint devices, this can possibly lead to overburdening the reader devices.